Blindfire - Alpha

I present Blindfire, a 2D top-down shooter in which several players cooperate to fight waves of enemies. As most enemies can’t be killed by a single player, and some are invisible to those who can kill them, communication between the players is neccessary in order to survive.
The game requires at least two players, each with a smartphone, and uses bluetooth to connect smartphones. It currently has 30 levels, several achievments, and the graphics and UI are customizable.

I would appreciate feedback and ideas for the game, and can be reached at ron.solan.work@gmail.com .
A link to the play store

A screenshot of the game: